1. Technical Field
The present specification describes a liquid discharging device and an image forming apparatus, and more particularly, a liquid discharging device and an image forming apparatus for discharging liquid onto a recording medium to form an image on the recording medium.
2. Discussion of the Background
An image forming apparatus, such as a copying machine, a printer, a facsimile machine, a plotter, or a multifunction printer having two or more of copying, printing, scanning, and facsimile functions, forms an image on a recording medium (e.g., a sheet) by discharging liquid. For example, the image forming apparatus includes a liquid discharging device for discharging liquid (e.g., an ink drop) onto a conveyed sheet. The ink drop is adhered to the sheet to form an image on the sheet. The liquid discharging device includes a liquid discharging head (e.g., a recording head) including a nozzle. The ink drop is discharged from the nozzle.
When ink having an increased viscosity, dried ink, or a foreign substance (e.g., dust) is adhered to an outer surface of the nozzle, the nozzle may be clogged. Similarly, when air bubbles are generated inside the nozzle, an ink drop may not be properly discharged from the nozzle.
To address these problems, a maintenance-recovery mechanism for maintaining the recovering reliability of the liquid discharging head is provided in the liquid discharging device. To do so, the maintenance-recovery mechanism may perform a sucking operation, a wiping operation, and a blank-discharge operation. In the sucking operation, a cap included in the maintenance-recovery mechanism caps the nozzle of the liquid discharging head and a pump connected to the liquid discharging head then sucks ink contained in the liquid discharging head through the nozzle. In the wiping operation, a wiper blade, included in the maintenance-recovery mechanism and formed of an elastic member such as rubber, wipes a nozzle surface of the liquid discharging head on which the nozzle is provided. In the blank-discharge operation, the liquid discharging head discharges ink not used for forming an image so as to remove ink having an increased viscosity and mixed-color ink from the inside of the nozzle and the outer surface of the nozzle. A combination of the sucking operation, the wiping operation, and the blank-discharge operation removes the ink having the increased viscosity, the foreign substance, and the air bubbles from the liquid discharging head, so that the liquid discharging head may discharge an ink drop properly and stably.
One example of the maintenance-recovery mechanism includes a wiper blade for wiping a liquid discharging surface of a liquid discharging head. A wiper holder holds the wiper blade such that the wiper blade wipes the liquid discharging surface by application of constant pressure on the liquid discharging surface.
Another example of the maintenance-recovery mechanism includes a blade for wiping a liquid discharging surface of a liquid discharging head. The blade is provided on an outer circumferential surface of a belt, and a platen contacts an inner circumferential surface of the belt.
To form an image at an increased speed, the image forming apparatus may include a long, liquid discharging head corresponding to a width of a sheet. To wipe the long, liquid discharging head, the belt carrying the blade needs to be long as well. However, such a long belt may be warped by gravity, and therefore the blade may not wipe a liquid discharging surface of the long, liquid discharging head by applying constant pressure on the liquid discharging surface. Moreover, even when the platen contacts the inner circumferential surface of the belt, the belt and the platen are longer than the long, liquid discharging head, and therefore, when the blade provided on the belt separates from the long, liquid discharging head, the blade, which is contacted and bent by the liquid discharging surface, is suddenly straightened and thereby may scatter liquid adhered to the blade.